Some local traffic and government business in Shanghai was disrupted on Friday as a result of earth subsidence blamed on water seepage in a cross-river rail tunnel.

A dyke is broken by the Huangpu River in Shanghai on July 2, 2003. The accident was caused by earth subsidence blamed on work on nearby cross-river rail tunnels. The dyke began slowly sinking on Tuesday night and the wall cracked in the small hours of Wednesday because of the combined effects of subsidence and the rising night tide.[newsphoto.com.cn]

Authorities are taking emergency measures to repair the damage and prevent a repeat of the problem, which first emerged earlier this week.

Water began to seep into the M4 rail tunnel and the ground began to sink near Zhongshan South Road on Tuesday.

The instability cracked a floodwall and caused the collapse of one building and structural damage to several others.

Authorities have been forced to close some roads in the area and reroute many public transport lines

Several finance and tax departments nearby, such as Shanghai Municipal Finance Supervision Bureau, have also had to relocate temporarily.

The electricity department has removed 1,000 high and low tension power lines to remove potential hazards.

But local residents are still supplied with water and electric and have suffered few disruptions to their normal lives, local officials said.

Premier Wen Jiabao has asked Minister of Construction Wang Guangtao to lead a special team to Shanghai to oversee the local emergency repair work. Wen also urged local officials to protect the lives and property of local residents and to help prevent flooding.

And Shanghai government has launched a month-long inspection campaign to check for buildings at risk of subsidence.

Hundreds of armed police are also strengthening the floodwall of Haungpu River to prevent more water from pouring into the tunnel and causing more subsidence in other riverside areas.